Problem: If $x \bigtriangledown y = 5x+y$ and $x \boxdot y = (6-x)(y)$, find $1 \bigtriangledown (4 \boxdot -2)$.
Answer: First, find $4 \boxdot -2$ $ 4 \boxdot -2 = (6-4)(-2)$ $ \hphantom{4 \boxdot -2} = -4$ Now, find $1 \bigtriangledown -4$ $ 1 \bigtriangledown -4 = (5)(1)-4$ $ \hphantom{1 \bigtriangledown -4} = 1$.